The present invention relates to an improved weld grinding apparatus and, more particularly, to a semiautomatic weld grinding apparatus capable of grinding off excess weld from a saddle-type weldment joining two perpendicularly oriented tubular sections wherein the weld grinding head follows a circular path through a plurality of planes as the saddle-shaped weldment is traversed. The invention also relates to an improved welding or cutting apparatus wherein the weld grinding head is replaced with either a welding head or a flame cutting head that follows the saddle-shaped path created at the interface of two perpendicularly disposed tubular sections.
The machining apparatus herein presented essentially replaces the manually operated grinding stones or wheels and the portable abrasive belt grinders heretofore used to remove excess weld from a saddle-shaped weldment joining a nozzle to a shell. The prior art method of grinding was a long, tedious, inefficient operation that was not very accurate and was more hazardous to the grinder operator, exposing the operator to abraided airborne materials and to above the ground walking about a shell that often exceeded ten feet in outside diameter, such above ground work often requiring the installation of scaffolding. Similar prior art deficiencies are applicable to welding and cutting operations, all of which are basically overcome through the use of present invention.
Relevant prior art can be found in the disclosures of Cink, U.S. Pat. No. 2,878,010 and Salotti et al, U.S. Pat. No. 3,172,937. Cink provides an operating tool effective zone and a follower-roller at the same radius relative to the co-axial rod, the path traced by the effective zone of the tool being the exact path of the line of intersection of the surfaces of the intersecting or to be joined cylinders. The present invention, however, provides for independent adjustment of both the cam follower assembly and the operating tool relative to the shaft which is co-axial with the nozzle. By adjusting the radius of the cam follower assembly such that, when rotated, its rise and fall in following the surface of the cam matches the desired rise and fall of the tool, the tool path will approximate the path of the line of intersection of the cylinders. Therefore, by providing radial adjustment of the cam follower assembly and operating tool relative to the shaft, the present invention provides an apparatus which utilizes a single cam operable through a plurality of cylinder sizes and cylinder size ratios to accomplish grinding, welding or cutting as the tool follows the saddle-shape curve formed by the junction of two perpendicularly oriented cylinders. In Cink and in Salotti et al, the cam or template used has a one to one correspondence such that the tool path trace mirrors the cam followed, thereby necessitating an inventory of cams for different curvatures, whereas the apparatus of the present invention is operable over a variety of curved surfaces utilizing a single cam or template, notwithstanding a vast potential combination of cylinder sizes.